giffords was shot in a mass shooting in arizona. >> reporter: newtown connecticut, portland oregon, aurora, colorado, there's been more than 10 mass shootings since january 8, 2007. when a gunman opened fire in tucson arizona. >> my 6-year-old daughter was killed in a mass shooting in arizona. i have one question for lawmakers, when are you going to do something about gun violence. >> reporter: arizona senator giffords was also shot. the massacre in newtown connecticut was a decisive moment. >> how was newtown? >> it brought back a lot of memories about what that was like. so two years ago today. and you hope that this kind of thing doesn't happen again.